Triazine


Triazine

A triazine is one of three organic chemicals, isomeric with each other, whose empirical formula is carbon3hydrogen3nitrogen3.

Structure

The triazine structure is a heterocyclic ring, analogous to the six-membered benzene ring but with three carbons replaced by nitrogens. The three isomers of triazine are distinguished from each other by the positions of their nitrogen atoms, and are referred to as 1,2,3-triazine, 1,2,4-triazine, and 1,3,5-triazine. Other aromatic nitrogen heterocycles are pyridines with 1 ring nitrogen atom, diazines with 2 nitrogen atoms in the ring and tetrazines with 4 ring nitrogen atoms. Triazines are weaker bases than pyridine.

Uses

The best known 1,3,5-triazine derivative is melamine with three amino substituents used in the manufacture of resins. Another triazine extensively used in resins is benzoguanamine. Triazine compounds are often used as the basis for various herbicides such as cyanuric chloride (2,4,6-trichloro-1,3,5-triazine). Chlorine-substituted triazines are also used as reactive dyes. These compounds react through a chlorine group with hydroxyl groups present in cellulose fibres in nucleophilic substitution, the other triazine positions contain chromophores.

A series of 1,2,4-triazine derivatives known as BTPs have been considered in the liquid-liquid extraction community as possible extractants for use in the advanced nuclear reprocessing of used fuel. [http://www.nea.fr/html/pt/docs/iem/madrid00/Proceedings/Paper14.pdf] [http://www-atalante2004.cea.fr/home/liblocal/docs/atalante2000/P3-26.pdf] [ [http://www.nea.fr/html/pt/docs/iem/jeju02/session2/SessionII-15.pdf Development Of Electrochemical Separations Of Uranium And Re Elements From Fluoride Melts ] ] [http://www.rsc.org/delivery/_ArticleLinking/DisplayArticleForFree.cfm?doi=b301178j&JournalCode=DT] [http://www.tntech.edu/WRC/pdfs/Projects04_05/Ens_Elem.pdf] BTPs are molecules containing a pyridine ring bonded to two 1,2,4-triazin-3-yl groups.

Synthesis

1,2,3-Triazines can be synthesized by thermal rearrangement of 2-azidocyclopropenes. 1,2,4-Triazines are prepared from condensation of 1,2-dicarbonyl compounds with amidrazones. A classical triazine synthesis is also the Bamberger triazine synthesis. Symmetrical 1,3,5-triazines are prepared by trimerization of cyanogen chloride or cyanimide. Benzoguanamine (with one phenyl and 2 amino substituents) is synthesised from benzonitrile and dicyandiamide in dimethoxyethane with potassium hydroxide. ["Benzoguanamine" J. K. Simons and M. R. Saxton Organic Syntheses Coll. Vol. 4, p.78; Vol. 33, p.13 [http://www.orgsyn.org/orgsyn/prep.asp?prep=cv4p0078 Article] ]

Reactions

Although triazines are aromatic compounds the resonance energy is much lower than in benzene, and electrophilic aromatic substitution is difficult but nucleophilic aromatic substitution more frequent.2,4,6-Trichloro-1,3,5-triazine is easily hydrolyzed to cyanuric acid by heating with water at elevated temperatures. 2,4,6-Tris(phenoxy)-1,3,5-triazine reacts with aliphatic amines in aminolysis, and this reaction can be used to give dendrimers. [Christian Dreyer, Alfred Blume, Monika Bauer, Jörg Bauer, Jens Neumann-Rodekirch Fourth International Electronic Conference on Synthetic Organic Chemistry (ECSOC-4), September 1-30, 2000 [http://pages.unibas.ch/mdpi/ecsoc-4/a0098/a0098.htm Article] ] Pyrolysis of melamine under expulsion of ammonia gives the tri-s-triazine melem. [Barbara Jürgens, Elisabeth Irran, Jürgen Senker, Peter Kroll, Helen Müller, and Wolfgang Schnick J. Am. Chem. Soc., 125 (34), 10288 -10300, 2003. [http://pubs.acs.org/cgi-bin/jcen?jacsat/125/i34/html/ja0357689.html Abstract] ] Cyanuric chloride assists in the amidation of carboxylic acids. ["Triazine-Promoted Amidation of Various Carboxylic Acids" Jeremy Schlarb 1999 [http://www.heidelberg.edu/depts/chm/triazine.html Article] ]

The 1,2,4-triazines can react with electron-rich dienophiles in an inverse electron demand Diels-Alder reaction. This forms a bicylic intermediate which normally then extrudes out a molecule of nitrogen gas to form an aromatic ring again. In this way the 1,2,4-triazines can be reacted with alkynes to form pyridine rings. An alternative to using an alkyne is to use norbornadiene which can be thought of as a masked alkyne.

Notes

References

* "Heterocyclic Chemistry" T.L. Gilchrist 1985 ISBN 0-58201-421-2 (1997, ISBN 0582278430)

ee also

* Pyridine
* Tetrazine


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  • Triazine — Triazine,   sechsgliedrige heterozyklische Verbindungen, die drei Stickstoffatome im Molekülring enthalten. Von den drei stellungsisomeren Verbindungen haben v. a. das 1,3,5 Triazin und seine Derivate (u. a. Melamin, Guanamine) in der… …   Universal-Lexikon

  • triazine — [trī′ə zēn΄, trī′əzin; trī az′ēn, trī az′in] n. [ TRI + AZINE] 1. any of three isomeric heterocyclic compounds having the formula C3H3N3 2. any derivative of these …   English World dictionary

  • Triazine — Les trois isomères de la triazine Une triazine est l un des trois isomères du composé organique constitué d un hétérocycle aromatique de six atomes, dont trois de carbone et trois d azote. Chacune a donc pour formule C3H3N3. Sommaire …   Wikipédia en Français

  • Triazine — 1,2,3 Triazin (links), 1,2,4 Triazin (Mitte) und 1,3,5 Triazin (rechts). Als Triazine wird eine Stoffklasse chemischer Verbindungen bezeichnet, deren Grundstruktur ein aromatischer Heterocyclus ist. Die meisten Triazine sind 1,3,5 Triazine, bei… …   Deutsch Wikipedia

  • triazine — triazinas statusas T sritis chemija apibrėžtis Šešianaris heterociklinis junginys. formulė C₃H₃N₃ atitikmenys: angl. triazine rus. триазин …   Chemijos terminų aiškinamasis žodynas

  • triazine — noun Etymology: International Scientific Vocabulary Date: 1894 any of three compounds C3H3N3 containing a ring composed of three carbon and three nitrogen atoms; also any of various derivatives of these including several (as atrazine and… …   New Collegiate Dictionary

  • triazine — /truy euh zeen , zin, truy az een, in/, n. Chem. 1. any of a group of three compounds containing three nitrogen and three carbon atoms arranged in a six membered ring and having the formula C3H3N3. 2. any of a number of their derivatives. [1890… …   Universalium

  • triazine — noun Any of three isomeric aromatic heterocycles containing three carbon atoms, three nitrogen atoms and three double bonds …   Wiktionary

  • Triazine — Tri|azi|ne die (Plur.) <zu ↑tri... u. ↑Azine> sechsgliedrige Verbindungen, die drei Stickstoffatome im Molekülring enthalten (Chem.) …   Das große Fremdwörterbuch

  • triazine — n. chemical compound which contains three nitrogen atoms and three carbon atoms all in a ring (Chemistry) …   English contemporary dictionary


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